(1) Field of the Invention
This invention relates to semiconductor device package, particularly to surface mount light emitting diode (LED) package.
(2) Brief Description of the Related Art
In semiconductor technology, surface mount packages are sometimes used to hold one semiconductor chip on front side of a substrate and contact to a mother board is made on backside of the substrate. FIG. 1 shows a prior art package for mounting a LED chip on one side of a substrate 13. The package has two metal terminals 11 and 12 for external connection. The metal terminal 11 is an extension of a landing on which a semiconductor chip 10 is mounted. In the backside of the substrate, there are corresponding metal terminals. The terminals 11,12 are connected to a corresponding terminals in the back through a semicircular plated through conduit 151 and 152.
The chip 10 has two electrodes 101 and 102 connected by wires 103 and 104 respectively to the terminals 11 and 12. The wires 103, 104 are compressed on the terminals 11 and 12 respectively for bonding. The compression creates an expanded compressed area 16. This compressed area occupies a width d1. The semicircular conduit occupies a width d2. The chip requires a width d3 for mounting. Thus the total width W1 is equal the total of d1, d2 and d3, i.e. W1=2d1+2d2+d3.
For low cost production, it is important to reduce the size of the package. For a display panel composed of a large number of the LEDs, a closer packaging can increase the light intensity and higher resolution. Therefore, a smaller LED package is what the industry is striving for.
An object of this invention is to reduce the package of a surface mount semiconductor package. Another object of this invention is to reduce the dimension of LED package. Still another object of this invention is to increase the light intensity and resolution of an LED display panel.
These objects are achievement by placing the plated-through conduits at the corners of the package, so that the expanded compressed area is offset from and lined up vertically with the conduit, thus reducing the total horizontal width of the package.